The Knights of the white wolf sprue is an upgrade on the normal knights, they are included in each knightly order regiment box, so if you want to make knights of the white wolf you can just buy such a box, if on the other hand you want the sprue for converting some mordheim mini's (middenheimers come to mind) you will have to look on ebay or other auction sites, they are avaiable every so often

btw: Please understand the fundamental concept that opinions are like belly buttons, we all have one but they donít hold much water.

I got same problem as you do I'm building an extremly (to the edge af fanatisme) Sigmarite themed Ostland army based around the Knights of Sigmar's righteous fury, an templar order I invented myself and for my knights on foot (or great-hammerers) I recently bought the greatswords box and stolen received some Chaos hammers from a friend. I still have to begin construction though. Off course if you want koww you would be better off with the knightly order box and a greatswords box since that way you also get the iconography of koww

Alternativly you could buy some Teutogen Guard, they were released by GW for the Storm of Chaos Campaign and represent knights from Middenheim. A quick google search will reveal what I mean. unfortunatly they are very rare!

Whatever you do, please keep us updated in the miniatures section, i'm extremly interested in your progress for obvious reasons!